A dynamic nuclear polarization (DNP) system may be utilized to prepare contrast agents (e.g., 13C1-Pyruvate) for imaging via imaging modalities such as magnetic resonance imaging (MRI) and nuclear magnetic resonance (NMR) spectroscopy. Increasing a polarization of the nuclear spins of the contrast agents may increase a sensitivity of the imaging modalities. In order to provide conditions for increasing the polarization of the nuclear spins, a temperature of the contrast agents is decreased by positioning the contrast agents within a container (e.g., a vial) and submerging the container into a bath of liquid helium within a vacuum chamber of the DNP system. In order to retain the liquid helium within the vacuum chamber, an inlet opening of the vacuum chamber may be closed by a sterilized sealing system. A magnetic field is produced across the vacuum chamber by one or more magnets of the DNP system, and the contrast agents are hyperpolarized by microwave radiation at an appropriate frequency from a microwave radiation source of the DNP system. The hyperpolarized contrast agents may be mixed with a dissolution medium such as an aqueous solution of sodium hydroxide and tris(hydroxymethyl)aminomethane and may be transported to a location external to vacuum chamber for analysis via MRI, NMR, or other imaging modality.